Gumbo must (4)
I believe the answer is:
okra
'gumbo must' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for okra that I've seen before include "Ladies' fingers with edible pods" , "old ladies' fingers" , "Green pods, in stews" , "Tropical plant with edible pods" , "Long green tropical vegetable" .)